Insulator.



I. I. IRWIN.

- msuLAToR. APPLICATION FILED DEC.30| 1916.

Patented June 12, 1917.

JOHN' J'. IRWIN, 0F CLEVELAND, OHIO.

INsULnToR.

Specification of Letters Patent.

Patented J une 12, 191 '7.

Application led December 30, 1916. Serial No. 139,808.

To all 'whom it may concern.'

Be it known that I, JOHN J. IRWIN, a. citizen of the United States,residing at Cleveland, in the county State of Ohio, have invented acertain new and useful Improvement in Insulators, of which the followingis a. full, clear, and exact description, reference being had to theaccompanying drawings.

This invention relates to an improved insulator for supporting telephoneand telegraph wires or other like electrical conductors, and is of theclass known to the trade as the saddle-top insulator, that is, of thesort having a transverse groove in its top within which the line wirerests, in contradistinction to a very common form of insulator having acircumferential groove for the retention of atie wire by which the linewire is lashed to the side of the insulator.

The. numerous advantages of a properly designed saddle-top insulatorover that having only the circumferential groove-such as itsfacilitating the removal of slack from a comparativelylong stretch ofwire, and its expediting the construction of the line, because of itsability to support the line wire in a well insulated condition even inthe absence vof tie wire-are well known and thoroughly appreciated bypersons familiar with the general subject of line'wire support but, inthe use of all saddle-top insulators with which I am familiar the difiifculties are experienced of the insulators breaking due to the strainsimposed upon them by the line wire by reason of their improper design,and ofv thebreaking of the line wire because of the distortion to whichit is subjected by the-wire-holding or engaging parts of the insulators.

In all insulators of the class to which my improvements belong (as wellas in the insulators of the circumferential groove type), tie wires ortheir equivalents are required for holding the line wire againstdisplacement. The conditions sought for and which should exist in aninsulator are these: The insulator should support the line wirepractically without the need (so far as the support is concerned) ofties and without imposing upon the line wire any biting, bending orstraining effect other than results from the weight of the wire; and thetie wire should full its function of holding the of Cuyahoga and y linewire against displacement without kinking or pinching the wire or in anyway injuring it. l

It is the object of my invention to provide, at no than in the case ofinsulators of the prevailing type, an insulator possessing the desirablequalities above mentioned, and having associated with it (in a morelimited phase of the invention) a tie wire of peculiar formation thatwill eli'ectually hold the line wire against displacement withoutdamaging it.

To this end my invention consists in producing an electric wiresupporting and insulating device having the characteristics set out inthe claims annexed hereto and specifically described hereinafter byreference to the accompanying drawing which forms a part hereof, andwherein Figure l is a perspective view of my improved insulator in use;Fig. 2 is a section through the insulator in the vertical plane of theline wire; and Fig. 3 is a fragmentary vertical section at right anglesto Fig. 2.

The body portion l of the insulator is provided with the usual threadedsocket 2 for the reception of the threaded upper end of a peg 3 whichmay be carried by a cross arm 4. The upper end of the body portion isenlarged to form a crown 5, the periphery of which overhangs theadjacent part of the body portion vin `order to produce a downwardlyfacing circumferential ledge or shoulder 6. Y

A transverse groove 10 is formed in the top of the insulator, and thebottom of this groove, which is shown as straight, is spaced below theplane of the shoulder 6 a distance substantially equal to the combineddiameters o r thicknesses of the line wire and the tie wire, for animportant reason which will be explained hereinafter. I do not considerit so essential that the bottom of the groove 10 be absolutely straight,but it is important that the portion whereon the line wire rests isspaced lthe aforesaid dista-nce below the plane of the ledge.

The line wire, which is represented at 12, lies upon the bottom of thegroove 10, and the central portion of a tie wire 13 is passed about theinsulator body in contact with the shoulder or ledge 6 and above theline wire. Upon one side oftheinsulator body the tie greater expense ofproduction wire is crossed as indicated at 14, and is then carriedbackward on each side of the insulator and beneath the line wire whereits ends are twisted spirally about the line wire in both directionsfrom the insulator, the extreme end portions of the tie wire beingturned backward upon themselves.

It will be observed that the space between the line wire and the ledgeor shoulder 6 is ample to receive the tie wire so that the tie wire doesnot exert any pressure upon the line wire7 and it will be explained thatthe end portions of the tie wire are twisted about the line wire in sucha manner as to avoid any possible injury to the line wire. Especially inhard drawn copper wire, which is practically exclusively used in.telegraph Work, any kinking, pinching or undue bending of the wire,particularly if it is sufficient to break the surface of the wire,greatly impairs the strength of the wire and is likely to result in thewires breaking. For this reason the insulator should support the linewire straight and free from kinks or bends under all circumstances,whether the wire is covered with ice, snow, or other weighty matter, oris free from such encumbrances. This result is assured in the use of myimproved insulator.

While it is essential that the line wire be supported far enough belowthe shoulder or ledge 6 to .permit the tie wire to be received betweenthem without its exerting any pres.- sure upon either, it is fully asimportant that no more space be left between the ledge and line wirethan is required to attain this pend, for if there were, the line wirewould lie free to move with the result that it would be chafed byrubbing against the sides or bottom of the groove and against the tie.wire,

and thus in]ured, or the tie wire would become weakened by the vibrationof its end portions. Therefore the proportions herein set forthconstitute the essence of my invention.

Having thus described my invention what I claim is:

1. An insulator comprising a body portion having a downwardly facingledgev adapted to be engaged by atie wire, and having also a transversegroove for the reception of a line wire, groove being spaced below theplane of the ledge a distance substantially equal to the combinedthicknesses of the tie wire and line wire.

2. An insulator comprising a body portion having a circumferentialdownwardly facing ledge that is adapted to be engaged by a tie wire, andhaving also a transverse groove for the reception of a line wire thebottom whereof is straight and spaced below the plane of the aforesaidledge a disthe bottom of the` tance. substantially equal to the combinedthicknesses of the tie wire and line wire.

3. An insulator comprising a body portion which terminates at its upperend in an enlarged crown the periphery of which overhangs the adjacentend 4of the body portion to form a downwardy facing ledge that isadapted to be engaged by a tie wire, the body portion being providedwith a transverse groove which extends downward through the crown andhas a straight bottom upon which a line wire is adapted to rest andwhich is spaced below the plane of the aforesaid ledge a distancesubstantially equal to the combined thicknesses of the tie wire and linewire.

4. In a wire supporting device of the character set forth, thecombination of an insulator body having a circumferential downwardlyfacing ledge that is adapted to be engaged by a tie wire, transversegroove in its reception of a line wire, the wire supporting portion ofthe groove being spaced below said ledge a distance substantially equalto upper end for the l,the combined thicknesses of the tie wire and linewire, and a tie wire which passes about the body above the line wire andin engagement with the ledge thereby to maintain the line wire incontact with the wire supporting portion of the groove.

5. In a wire supporting device of the character set forth, thecombination of an insulator body having a circumferential downwardlyfacing ledge that is adapted to be engaged by a tie wire, and havingalso a transverse groove in its upper end for the reception of a linewire, the bottom of the groove being spaced tance substantially equalto' the, combined thicknessesof the tie wire and line wire, and a tiewire which passes about the body above the line wire and in engagementwith the ledge and is crossed over itself on one side of the body andcontinues about the same in both directions to where its opposite endsare twisted spirally about the line wire and away from the insulator insuch cerdition as to permit the line wire to remain undistorted by theinsulator or tie wire.

6. An insulator comprising a body portion having a downwardly facingledge adapted to be engaged by a tie wire, and having also a transversegroove for the reception of a line wire, the wire supporting portion ofthe groove being spaced low the plane of the ledge a distancesubstantially equal to the combined thicknesses of the tie wire and linewire. f

In testimony whereof, I hereunto aiix'my signature.

JOHN J. IRWIN.

below said ledge a dis-4 and having also a

